ALTDQ_DQS2 IP Core User Guide

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ID 683742
Date 5/08/2017
Public
Document Table of Contents
Document Table of Contents x
ALTDQ_DQS2 IP Core User Guide
ALTDQ_DQS2 IP Core User Guide x
ALTDQ_DQS2 Features ALTDQ_DQS2 Device Support Resource Utilization and Performance ALTDQ_DQS2 Parameter Settings ALTDQ_DQS2 Data Paths ALTDQ_DQS2 Ports Dynamic Reconfiguration for ALTDQ_DQS2 Stratix V Design Example Arria V Design Example IP-Generate Command ALTDQ_DQS2 IP Core User Guide Archives Document Revision History
ALTDQ_DQS2 Data Paths x
DQ and DQS Input Path DQ and DQS Output Path
DQ and DQS Input Path x
DQ and DQS Input Paths for Stratix V Devices Data Input Path for Arria V, Cyclone V, and Stratix V Devices Blocks in DQ and DQS Data Input Path
Blocks in DQ and DQS Data Input Path x
DQS Logic Capture DDIO to Read FIFO Path FIFO Control
DQ and DQS Output Path x
DQ and DQS Output Path for Stratix V Devices Blocks in DQ and DQS Output Path DQ and DQS Output Path for Arria V and Cyclone V Devices
ALTDQ_DQS2 Ports x
ALTDQ_DQS2 Data Strobe Ports ALTDQ_DQS2 Data Ports ALTDQ_DQS2 Termination Control Ports ALTDQ_DQS2 PLL and DLL Ports ALTDQ_DQS2 Hard FIFO Ports ALTDQ_DQS2 Dynamic Configuration Ports
Dynamic Reconfiguration for ALTDQ_DQS2 x
I/O Configuration Block Bit Sequence for Arria V GZ and Stratix V Devices DQS Configuration Block Bit Sequence for Arria V GZ and Stratix V Devices I/O Configuration Block Bit Sequence for Arria V and Cyclone V Devices DQS Configuration Block Bit Sequence for Arria V and Cyclone V Devices Example Usage of Dynamic Reconfiguration for ALTDQ_DQS2
Stratix V Design Example x
Instantiating ALTDQ_DQS2 IP Core Instantiating the ALTDLL IP Core Instantiating ALT_OCT IP Core Instantiating Altera PLL Setting Up NativeLink and Simulation Settings Understanding Simulation Results—Stratix V Design Example
Instantiating Altera PLL x
Altera PLL Clock Settings Information
Understanding Simulation Results—Stratix V Design Example x
Dynamic Configuration SDC Walkthrough
Dynamic Configuration x
DQS Write Operation Side Read Operation Side Write Operation DQS Read Operation Simulation Results
DQS Read Operation x
DQS Delay Chain Hard Read FIFO
SDC Walkthrough x
Analyzing Same Edge Transfer Constraining Outgoing DQS Strobe
Arria V Design Example x
Instantiating the ALTDQ_DQS2 IP Core Instantiating the ALTDLL IP Core Instantiating ALT_OCT IP Core Instantiating Altera PLL Setting Up NativeLink and Simulation Settings Understanding Simulation Results—Arria V Design Example
Instantiating Altera PLL x
Altera PLL Clock Settings Information
Understanding Simulation Results—Arria V Design Example x
Dynamic Configuration
Dynamic Configuration x
DQS Write Operation Side Read Operation Side Write Operation DQS Read Operation Simulation Results SDC Walkthrough
DQS Read Operation x
DQS Delay Chain VFIFO, LFIFO, and Read FIFO DQS Enable Control
SDC Walkthrough x
Analyzing Same Edge Transfer Constraining Outgoing DQS Strobe Timing Violation tq_analysis.tcl
IP-Generate Command x
Using IP-Generate Command
ALTDQ_DQS2 IP Core User Guide

FIFO Control

For Arria V and Cyclone V devices, in addition to the read FIFO and the data valid FIFO, the location of the latency shifter FIFO is in each DQS group. The latency shifter FIFO takes in a read‑enable command from the core and implements a programmable latency of up to 32 cycles before feeding into the read-enable port of the read FIFO.

You can use the output of the data valid FIFO to perform the following tasks:

  • To ungate the DQS logic when a strobe signal is capturing the data. In this case, the write-enable port must always be '1' on the read FIFO.
  • To enable the read FIFO write-enable port when a clock is in use.

The following figure shows the three FIFOs interconnection.

Figure 3. Data Valid FIFO, Latency Shifter FIFO, and Read FIFO Interconnection


When a read command is sent to the memory device, a read-data-enable token is pushed through the data valid FIFO and the latency shifter FIFO. The data valid FIFO implements a latency equal to the read command to data latency. When the token comes out of the data valid FIFO, the DQS signal is ungated. The latency shifter FIFO then creates enough space between write and read pointers in the read FIFO to ensure that the data read on the read side is correct. If the read FIFO is read at half-rate, the read FIFO also implements a full-rate to half-rate conversion.

The determination of the correct latencies to implement at each of these FIFOs is important and cannot be done during compilation. When you attempt to implement your own custom memory solution, you must also implement some form of calibration algorithm.

To determine if the data coming from the read FIFO is valid, you must implement the read data valid latency in soft logic.

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